Pay attention to the capacity of the hall and whether there are places to sit, as well as whether these are fixed or mobile. Venues like these usually offer sound engineering services and equipment.
A classic training session works best with an absence of tables, a loose configuration of chairs, and a flipchart. Training sessions often last for more than 3 hours, so you might want to make sure that beverages are available at the venue (in the form of a water cooler, or perhaps a kettle).